D5000 Digital Media Scanning

Transcription

1 D5000 Digital Media Scanning Transition time shift (bit shift) and amplitude analysis Various defect detectors for simultaneous analysis of bit shift, missing pulses, super pulses, and thermal asperities Multi-threshold amplitude analysis at positive and negative signal peaks 24 detectors can run in parallel with different settings/thresholds Time shift (bit shift) analysis by zero-crossing detection for perpendicular recording High sampling rate for precise reconstruction of read-back signal High resolution of detection thresholds Real-time digital processing for high throughput 3D presentation of media defects Field upgradeable processing algorithms Specifications are subject to change without notice Rev. 09/17/2007 Part Number Copyright Guzik Technical Enterprises All rights reserved

2 Introduction D5000 Signal Analyzer opens new possibilities for media scanning. The analyzer can measure the amplitude defects (such as missing pulses, super pulses, and thermal asperities), and the time defects (such as transition shift). Up to 24 defect detectors can run simultaneously, with different settings. The high-resolution thresholds of the defect detectors and multi-threshold amplitude analysis allow the digital media scanner to generate three-dimensional map of the defects. Scanning Algorithm The typical signal used for media scanning is an HF pattern. This signal is read back as a high-frequency sine-wave signal. The read-back signal, digitized with high oversampling, controls digital P, which is running on frequency two times higher than the read-back signal. The phase of the P signal is adjusted such a way that each sample presents the positive and negative peaks of the read-back signal. The value of these samples allows you to analyze the amplitude defects on media. The position of zero-crossings of the read-back signal with respect to the P clocks (in case of perpendicular recording) presents a time shift (bit shift). The distribution of the zero-crossings is analyzed and qualified with respect to a detection window. The scanning algorithm is implemented within the DP5000 Digital Processor. This algorithm can be updated, when you install a new revision of WITE32. The DP5000 processor has the throughput high enough to process the signal from media without any delay, and then transfer all detected errors to the computer with high speed. High sampling rate and analog bandwidth allows D5000 Signal Analyzer to process a sine-wave signal with frequency up to 1.25GHz. 2 Copyright Guzik Technical Enterprises All rights reserved

3 Table 1 shows the defects, which can be detected with the D5000 Digital Media Scanning. Defect Read-back Waveform Detector Type Missing pulse or short group of missing pulses Missing Pulse Super pulse or short group of super pulses Super Pulse Modulation: small amplitude Missing Pulse Modulation: large amplitude Super Pulse Thermal asperity (Baseline shift) Thermal Asperity Amplitude asymmetry Thermal Asperity Time shift Time Shift T Table 1: Samples of Detected Media Defects Copyright Guzik Technical Enterprises All rights reserved 3

4 Figure 1 shows the disk area with a defect in the coordinates of track numbers and an angular head position with respect to the index. Different color shades correspond to different depth of the defect. Defect area Amplitude defects Down-track Direction Shade of color reflects defect depth Figure 1: Amplitude Defects Detected on Media 4 Copyright Guzik Technical Enterprises All rights reserved

5 The D5000 Digital Media Scanning includes 3D Viewer, which generates the three-dimensional map of a found defect. Figure 2 shows such map created for the zoomed-in area of the amplitude defect from Figure1. Figure 2: 3D Map of Amplitude Defect Figure 3 shows the time-shift distribution (bit-shift plot) of the scan area. Figure 3: Bit-shift Plot Copyright Guzik Technical Enterprises All rights reserved 5

6 D5000 Digital Media Scanning Requirements 1. Guzik D5000 Signal Analyzer 2. Guzik RWA-2000 series 3. Guzik V2002 or Canon spinstand 4. WITE32 Revision 3.40 or later 5. D5000 Digital Media Scanning license. Please contact to obtain a quotation for the license Wyandotte Street Mountain View, CA Phone: (650) Fax: (650) sales@guzik.com 6 Copyright Guzik Technical Enterprises All rights reserved